SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef46da5165694c2004d830012fe30491be6bbdaa7e68507fe96bbab5015a6a06' 
  AND token = 'u3pAwXuuil7UlIYAQKD8jAwoWfng3K2sxOLOyVpBs+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}